This invention relates to the archwire for orthodontics especially the archwire for orthodontics which consists of two or more wire components and a wire component. It is also related with the wire cutting tool used for cutting of the said wire component.
It is a principle that the main wire portions of the orthodontic archwire are on the same plane and the same axial center irrespective of the presence of loops. The main wire portion of the orthodontic archwire points to a portion without curvature, such as a loop in the orthodontic archwire here.
It was difficult and skillful work to bend two or more loops in the same form by hand using one wire component. It was also difficult and skillful work to make an orthodontic archwire with some loops according to the above-mentioned principle. Consequently, producing an orthodontic archwire with some loops needed long treatment times. A wire which was longer than the dental arch length of the patient was tried into the patient's mouth at the time of measurement, with the end of the wire pressed against the patient's oral mucosa. During this procedure the patient was in pain.
The preformed archwire with loops settled the above-mentioned faults. However, when treating orthodontics using a preformed archwire with loops, a variety of preformed archwires with different loop spacings, loop forms, etc. needed to be arranged, and inventory control was complicated as well. Moreover, a preformed archwire with loops was not used when the distance between loops was outside regulations. Furthermore, the preformed archwire with loops was not used, when the positions where loops would be placed were bilaterally asymmetrical, since the loops were arranged in symmetry. Moreover, since it was necessary to combine a setup of each distance between loops in order to obtain an archwire with loops of a large number like multi-loop edgewise archwire with the ready-made article, there was a problem that exceeding great numbers of wires had to be prepared. Thus, in the flexibility of a design of an archwire, and in the simplicity of stock management of an archwire, the preformed archwire was inferior in the case where the archwire was hand made.
On the other hand, the method which connects two or more wire components with a connector, produces the archwire for orthodontics as indicated by the U.S. Pat. No. 4,412,819 and the Japanese patent No. 6-34607.
In a composite orthodontic archwire according to the U.S. Pat. No. 4,412,819, the wire of an anterior segment 50 and the wires of posterior segments 51, 51 are connected with the connectors 52, 52 (FIG. 71). Since the ends of these two wires have overlapped in this connection structure, there was a misalignment in the axial center of these two wires 50, 51 (FIG. 72).
On the other hand, in a composite orthodontic archwire according to the Japanese patent No. 6-34607, the wire of the anterior segment 60 and the wires of the posterior segments 61, 61 are connected with the connectors 62, 62 (FIG. 73). Respective ends of these wires 60, 61 were connected by grips 62a, 62b of the connectors and arranged to the upper and lower sides or right and left (FIGS. 74 and 75). However, even if it was this connection structure, these two wires 60, 61 could not be connected with the same axial center, so there is a level difference.
Since a level difference arises between the axial centers of these wires, the connection structure of these wires does not meet the above-mentioned principle for the orthodontic archwire. For this reason, in using the archwires produced by these methods, in order to correct the misalignment of the axial center of the wires, the brackets and the archwires needed for adjustment, and this adjustment work was complicated.
Japanese patent 6-34607 also shows the connection structure without a level difference between axial centers of the wires (FIG. 76). However, since grips 62a, 62b for securing a wire were arranged in series, the size of the direction of an axial center of a connector is long. Therefore, when the distance between brackets was short, this connector was not used.
Moreover, with this technology, the connector needed to be simultaneously supported with respective wires at the time of connection, connection was not easy and positioning accuracy was bad.